Prior studies have demonstrated that psychological distress delays wound healing. In addition, there is evidence that older adults are at risk for delayed wound healing. Thus, it is particularly important to evaluate strategies for reducing delayed wound healing among older adults who are experiencing distress. Physical exercise is a behavioral approach that may contribute to enhanced wound healing both via influences on psychological functioning and via influences on neuroendocrine and immune parameters relevant for wound healing. This study is designed to evaluate the effect of exercise on wound healing among distressed older adults using a randomized controlled design. Eighty-five men and women ranging in age from 65-85 will be recruited and will undergo a pre-baseline experimental punch biopsy wound. After the wound has healed participants will be randomly assigned to either an aerobic exercise condition (AE) or a stretching and flexibility control condition (SF). Participants will complete assessments of cardiopulmonary endurance, psychological functioning, endocrine function, and immune function at two times: baseline prior to random assignment (T1), and at the conclusion of the 12-week intervention period (T2). Two weeks after the T1 assessment, all participants will return to the study assessment site for a second experimental punch biopsy wound procedure as well as assessments of immune function and cortisol secretion (T1 A). Four weeks later (T1B), participants will complete an additional assessment of immune function and cortisol secretion. Participants will remain in their assigned conditions until completing the T2 assessment. Data will be analyzed with linear mixed modeling and hierarchical regression. It is hypothesized that participants assigned to the AE condition will achieve significant improvements in cardiorespiratory function, decreased psychological distress, and accelerated rates of wound healing compared to the SF participants. In addition, AE participants will experience enhanced regulation of neuroendocrine and immunologic parameters not observed in the SF participants. Results of the study will indicate the degree to which exercise influences wound healing as well as the psychological and biological mechanisms that contribute to the effect of exercise on wound healing. In turn, the results may have- implications for treating older adults who suffer dermal wounds or are recovering from surgery.